Polarity responsive neutral relay selector



Aug. 16, 1932. 3 D CROCE 1,871,669

4 POLARITY RESPONSIVE NEUTRAL RELAY SELECTOR Filed Nov. 23, 1928 Cop/ml Canfro/ Drive INVENTOR 6flneroDe Croce.

ATTORNEY the relay 21 at the armature 25. The relay 21, when energized, opens the original energizing circuit for the relay 17 at the armature 20 and, as the relay 17' is deenergized, the armature 25 thereof returns to its normal position, thereby interrupting the energizing circuit of the relay 21. The relay 21, how ever, beingof the slow-release type, maintains its armature in the operated position for a short time interval, after which the armature 20 engages its back contact to reestablish the original energizing circuit for the relay 17. j

The same series of operations is repeated, and the alternate energization and deenergization of the relays 17 and 21 continues until the relay 16 is deenergized, or until the relay 19, or its associated relay 26, is energized, as will be described later.

It will be noted that one terminal of the winding of the relay 19 is connected to the negative battery terminal, whereas one ter minal of the winding of relay 26 is connected to the positive battery terminal. It will be obvious that these relays will be energized only when the remaining terminals thereof are connected to the opposite terminals of' the substation battery or the battery at the dispatchers ofiice when connected by a common return conductor as described hereinbefore.

If the key 23 is moved into engagement with its contact, which is connected to the positive battery terminal, current will'flow through the lowest conductor 12 and the uppermost contact of the relay 16, to the armature 24 of the relay 17 which is alternately attracted and retracted to engage its front and back contacts, respectively. When the armature 24 engages its. front contact, no result will be produced, since both terminals of the winding of the relay 26 will be connected to current sources having like polarities. When the armature 24 engages its back contact, however, a circuit is completed, through the winding of the relay 19, to the negative battery terminal. The relay 19, when energized, opens the original energizing circult for the relay 17 at the armature 18, and further operation of the relays 17 and 21 is precluded. The relay 19 simultaneously completes an energizing circuit, at its armature aflected, since both its terminals will be connected to negative battery terminal when the armature 24 of the relay 17 engages its back contact. When the said armature engages its front contact, however, acircuit is completed for the energization of the relay 26.

The relay 26, when energized, completes a locking circuit at its armature 29, for the relay 17 which thereafter remains energized and maintains the armature 24 in engagement with its front contact. At the armature 30, the relay 26 completes an obvious energizing circuit for the control relay 31.

From the foregoing description, it will be apparent that the system of my invention provides for the selective operation of one of two relays by means of current impulses of different polarities. It will be apparent that the control relays 28'and 31 may be employed to effect any desiredoperation, for example, the closing and tripping of a circuit breaker. In Fig. 1, however, the relays 28 and 31 are illustrated as controlling the circuit through a reversible motor 32 having forward and reverse field windings 33 and 34. The function of the motor is to adjust a rheostat 35 by means of a contact-bearing nut 36 which is threaded on the motor shaft 37. In the particular installation for which this system was designed, the rheostat 35 is so connected in the field winding circuit of a dis.-

tant generator that it is possible to control the voltage of the generator by means of the polarity-responsive relay selector which I have described.

The advantages of the system of my invention will probably be apparent from the foregoing description, but .I wish to point out that this system makes possible the selective operation of a plurality of-control devices so long as the supervisory-control system is stopped at the point controlled by relay 16,

One advantage of this system is that it employs only comparatively inexpensive neutral relays, avoiding'the more costly polar relays which have been utilized heretofore.-

Since various changes and modifications in the system, of my invention will be apparent to those skilled in the art, my invention should not be limited to the specific embodiment-described and disclosed herein, except as necessitated by the scope of the appended claims.

I claim as my invention:

1. A selecting system comprising a connecting-relay, a source of direct current, means for alternately energizing and deenergizing said relay, a pair of selecting relays, each provided with an operating coil, one terminal of each of which is connected to opposite polarities of said direct-current source to cause the selecting relays to be responsive only to voltages of positive and negative polarity, respectively, a control circuit, and means for energizing the control circuit with positive or negative voltage from the direct-.

current source, said connecting relay being provided with contacts to transfer said control circuit from one to the other of the operating circuits of the selecting relays, whereby the selecting relays-may be selectively controlled byimpressing positive and negative voltages onthe control circuit. y i 2. In a remote control system, in combination, a source of direct current, a pair of selecting relays, another pair of relays, energizing circuits for said other pair of relays to cause them to operate alternately, operating circuits for the selecting relays, one of said other pairof relays being disposed to alternately close the operating circuits of the selecting relays, means for impressing a positive or negative voltage on the operating circuits of the selecting relays, the operating coil of one of said selecting relays being connected to the negative terminal of said current source therebybeing disposed to respond to a positive voltage impressed on its operating circuit while the operating coil of other selecting relay is connected to the positive terminal of said current source thereby being disposed to respond to a negative voltage impressed upon its operating circuit, and means actuated by either selecting relay when energized to stop the periodic operation of the said other pair of relays to permit the continuation of the energization of the particular selecting relay operated as long as the voltage to which it responds is impressed on its operating circuit.

3. In a remote control system, in combination, a source of direct ourrent,a pair of selecting relays, another pair of relays, energizing circuits for said other pair of relays to cause them to operate alternately, operating circuits for the selecting relays, a single control circuit common to all the selecting relays, one of said other pair of relays being disposed to alternately connect the control circuit to the operating circuits of the selecting relays, means for selectively impressing positive and negative voltages on the control circuit, the operating coil of one of said selecting relays being connected to the negative terminal of said current source thereby being disposed to respond to positive voltage only impressed upon its operating circuit from the control circuit while the operating coil of the other selecting relay is disposed to respond only to negative voltage, impressed upon its operating circuit from the control circuit, means actuated by the selecting relay that is connected to the positive terminal of said current source thereby being energized when the one of said other pair of relays is in its open positive for preventing its further of pairs of selecting relays, operating circuits for said relays, another pair of relays associated with each pair of selecting relays, energizing circuits for said other pair of relays to cause them to operate alternately, means for selecting a desired pair of selecting relays for operation, said means being disposed to efiect the initial energization of the said other pair of relays associated with the desired selecting relays to cause them to alternately close and open the operating circuits of the selecting relays, means for selectively impressing positive and negative voltages on the operating circuits of the selecting relays, the operating coils of said relays being connected to opposite polarities of said current source thereby being disposed to respond only to voltages of opposite polarity impressedon their operating circuits, and circuit-controlling means actuated by the selecting relays when either becomes energized to prevent further operation of said other pair of relays thereby to cause the operating circuit for the operated selecting relay to be maintained until its operating voltage is removed from the operating circuit.

5. The combination with a control circuit, a source of direct current and means for utilizing the source of direct current to impress positive and negative voltages upon thecontrol circuit, of a pair of control relays, the first of which is disposed to be connected to said control circuit, means for energizing said first relay, means controlled by the first relay for energizing the second, the second relay of said pair being effective to deenergize the first relay whereby said relays operate alternately, a pair of selecting relays, said first control relay being operative to transfer said control circuit from the one to the other of the selecting relays, each of the selecting relays having one terminal connected to 0p posite polarities of the direct current source whereby the one or the other of said selecting relays, may be energized in accordance with the polarity of the voltage imposed upon the control circuit, and means whereby said selecting, relays complete a locking circuit for said first-mentioned control relay or interrupt its energizing circuit, depending upon which selecting relay is energized.

6. The combination With a control circuit,

a source of direct current and means for utilizing the direct current source to impress positive and negative voltages upon the control circuit, of a pair of control relays, the first of which is disposed to be connected to said control circuit, means for energizing said first relay from the direct current source, means controlled by the first control relay for energizing the second control relay, the second control. relay being effective to deenergize the first control relay whereby said relays operate alternately, and a pair of selecting relays, said first control relay being operative to transfer said control circuit from the one to the other of the-pair of selecting relays, each of said selecting relays having one terminal-connected to opposite terminals of the direct current source whereby the one or the, otherof said selecting relays may be energized in accordance With the polarity'of the voltage imposed upon the control circuit.

7.1L selecting system comprising an op era-tingcireuit, a pair of selecting relays disposed in circuit relation to be responsive to direct current of a predetermined polarity, a pair of control relays disposed in interlocking circuit relation, means for energizing one of said control relays to cause alternate energization thereof for effecting circuit-transferring operations of the operating circuit be tween said selecting relays, and means for supplying direct current of either polarity to said operating circuit to selectively operate said selecting relays, one of said selecting relays being efi'ective to complete a locking circuit for the first-mentioned control relay and the other to interrupt the energizing circuit thereon v 8. A control system comprising a direct current source, a pair of selecting relays for energizing respectively either one of a pair of independent operating circuits, one terminal of the operating coil of one of said relays being connected to one polarity of direct current source and one terminal of the operating coil of the other of said relays being connected to an opposite polarity of said direct current source, a control circuit, a conto said control circuit.

trol relay for transferring said control circuit from one of the operating coils of said relays to the other, and means for applying eithei polarity of said direct current source 9. In a control system, in combination. a source of direct current, a pair of selecting relays eachdisposed to control an independent circuit, and each having one terminal of its operating coil connected to opposite poiarities of said source 01 direct current, a control relay provided With an armature having back and front contacts associated therewith, said back contact being connected to one of said selecting relays and said front contact being connected to the other of said selecting relays, a second'control relay connected in circuit-relation With-said first-named control relay and disposed to be energized thereby v and to deenergi'ze said first control relay whereby said control relays are continuously alternately energized and deenergized, a control circuit connected to said armature, and a'control key connected to said control circuit and disposed to apply either polarityof said directcurrent source to said control circuit, thereby to operate the selecting relay con nected to the polarity opposite to the polarity to which said control key may be connected, 7

10. In a control system, in combination, a

source of direct current, apair of control trol circuit tothe remaining terminal of either or the operating coilsof said selectlng relays and a control key connected to sai control circuit'and disposed to 'apply either polarity ofsaid' direct current source to said control circuit, thereby to operate either of the selectingrelays depending on the polarity applied by the control key to the control circuit.

In testimony whereof I have hereunto subscribedmy name this 19th day of November,

' GENNERO DE CROCE. 

